fuel pump?

[ats1971]

So i got my 96 xj on the road. Drove it all weekend and then parked it for a couple hours, came out to start it and it wont start. It will crank over. Thought i might of been out of gas so i added some and nothing. I poured a little in the tb and it started up for a bit till it died out. So im assuming its not getting and fuel. Im thinking its either the fuel filter or pump. What are your thoughts.

 

[Renegade XJ]

First hook up a fuel pressure gauge to the fuel rail. It's easy to do as it has a valve stem looking valve on it that usually has an aluminum cap on it. It's located towards the front of the fuel rain pointing towards the drivers side. You should have 32 or 36psi ( I'm can't remember the exact number, maybe someone else can chime in on this). If you don't have a fuel pressure guage you can at least check to see if your getting fuel by using a small screw driver to push in the valve, it should squirt out fuel under pressure. Fuel pressure can be effected by the fuel pump, filter, and fuel pressure regulator.

 

[Original_MudButt]

49 psi +/- 5 psi = healthy fuel pump.

At the very least, turn the radio off and have a friend in the Jeep with the door closed turn the key to the on position but not start it.

The fuel pump should come on as soon as the key is turned and the pump will run for 1-2 seconds.

You should be able to hear it if you are kneeling behind the rear wheel.

If you get nothing, then try swapping in a known good relay under the hood.

It's my understanding that under "most circumstances" fuel pumps usually kind of peter out over a period of time. They don't usually just die instantly. But I really don't have much experience with fuel pump deaths...

Good luck, HTH!

Edit: The above info is what worked on my '98.... Some or all of it may not apply to your '96. YMMV....

 

[Ecomike]

First hook up a fuel pressure gauge to the fuel rail. It's easy to do as it has a valve stem looking valve on it that usually has an aluminum cap on it. It's located towards the front of the fuel rain pointing towards the drivers side. You should have 32 or 36psi ( I'm can't remember the exact number, maybe someone else can chime in on this). If you don't have a fuel pressure guage you can at least check to see if your getting fuel by using a small screw driver to push in the valve, it should squirt out fuel under pressure. Fuel pressure can be effected by the fuel pump, filter, and fuel pressure regulator.

FPR is part of the fuel pump in the gas tank starting in 96 (OBD-II era), and is 49 psi spec. Pre 96 was 29-39 psi, vacuum regualted at the fuel rail.

If there is some fuel, low pressure and sound in the tank the hose in the tank may have come loose.

OP, if you need to replace the pump, do NOT buy Airtex.

 

[Wayne Sihler]

Every time the pump failed in my 96 it just would not start. Working fine,shut off,next time to start = nothing...These were all Bosch/factory pumps.
Against advice here,,,,I have an Airtex in it now. YMMV

 

[Ecomike]

Every time the pump failed in my 96 it just would not start. Working fine,shut off,next time to start = nothing...These were all Bosch/factory pumps.
Against advice here,,,,I have an Airtex in it now. YMMV

Interesting. I wonder if the higher pressure 96-01 pumps fail faster than the earlier pumps (low pressure)?

 

[Wayne Sihler]

Interesting. I wonder if the higher pressure 96-01 pumps fail faster than the earlier pumps (low pressure)?

Faster ? I dont know.
96> 3 pumps=360,000
98> 1 pump= 230,000
87> 1 pump= 248,000
Well now that I see the numbers ? I do know the 96 has seen more off road time than the others, maybe vibration/shock is the problem.